An out-of-control Chinese rocket is plunging towards the Earth – with nobody really knowing where or when it might land.
It is one of the biggest objects ever to make an uncontrolled re-entry, and follows another similar event last year that caused damage in Ivory Coast.
The spacecraft delivered Tianhe, or the first core module of China’s planned space station, as part of a launch last week. The module made it into space as planned, and continues its orbit.
But the launch vehicle – known as Long March 5 – fell into an uncontrolled orbit that has left it in orbit, tumbling around the Earth.
Some of the pieces are expected to break up through re-entry. But other, large chunks may not, and could fall to the ground.
The nature of the rocket – the fact it is still a long way from the ground, is floating at an altitude not usually used by spacecraft, and the relatively limited information that the Chinese space agency will share – mean that it is hard to know where the rest of its journey will take it, though it is expected to fall to the ground in the coming days.
But experts have nonetheless been tracking it, in an attempt to learn more about where it will go.
Perhaps pre-eminent among those watchers is Jonathan McDowell. While his day job sees him work as an astrophysicist at the Harvard-Smithsonian Center for Astrophysics as part of the Chandra X-Ray Center, studying quasars and galaxies, he is also famous as a cataloguer and watcher of spacecraft.
He will give Independent readers an opportunity to ask anything they like about the spacecraft, and what it might mean.
Are we at risk? Is this going to happen more as the new space race continues? And how can it be stopped?
Put your questions below and we’ll put as many as we can to McDowell during a live stream that will be available to all registered users on Saturday.
All you have to do is register to submit your question by 4pm on Friday in the comments below.
If you’re not already a member, click “sign up” in the comments box to leave your question. Don’t worry if you can’t see your question – they’ll be hidden until we post the live stream recording in this article on Saturday morning.